1. Field of the Invention
The present invention relates to an ink, an ink cartridge containing the ink, and an image-recording method in which the ink is used.
2. Description of the Related Art
In known image-recording methods, inks that contain a self-dispersing pigment as a coloring material are used to improve the optical density of images. Although inks that contain a self-dispersing pigment can produce images having relatively high optical density, the images have low scratch resistance. It is proposed in Japanese Patent Laid-Open No. 2009-019198 and No. 2010-222417 that polyurethane polymer particles or acrylic polymer particles are added to an ink that contains a self-dispersing pigment to improve the scratch resistance of images. Japanese Patent Laid-Open No. 2009-019198 describes an ink that contains a self-dispersing pigment and polyurethane polymer particles. Japanese Patent Laid-Open No. 2010-222417 describes an ink that contains a self-dispersing pigment and acrylic polymer particles.